Influence Of Soil Conditions Research Articles

Establishment and growth of hawthorn in floodplains in the Netherlands

Dendrochronology was used to assess the influence of soil conditions, elevation and related inundation, climate fluctuations and vegetation cover on the establishment and growth of hawthorn in non-grazed river floodplains. Presence of forest influences the discharge capacity of the floodplain, therefore forest development needs to be considered in management plans. Although ring detection in hawthorn is difficult, clear dynamics in establishment and growth of this shrub species were found. Establishment was mainly influenced by inundation (length and height). The effect of inundation on establishment is location dependent; positive due to transport and deposition of seeds in higher areas, and negative due to drowning of young plants in lower locations. Extreme climatic events were found to influence establishment including a drought in 2003 and relatively low and high precipitation in 2004–2006 and 2007 respectively. These events combined with almost no inundation caused some anomalies in the time series for hawthorn establishment. Once above a certain height, hawthorn is able to withstand various abiotic disturbances occurring in these dynamic river floodplains. Excavated areas are enhancing forest development following hawthorn establishment and therefore these areas should be limited in size (e.g. by deeper and narrower excavations and thus a steeper transition towards the grasslands).

Early growth stage water management effects on the fate of inorganic N, growth and yield in rice

Water and nitrogen (N) play vital roles in rice (Oryza sativa L.) production. Water-saving management decisions can influence soil conditions (oxidation and reduction), and these soil conditions affect the fate of N in paddy soil. We designed three irrigation regimes, namely, conventional irrigation (Flooding), shallow water depth (SWD), and a Non-flooding treatment, for our study. For the Flooding treatment, a ponding water depth of 0.05–0.06 m was maintained for 99 days after transplanting (DAT), and the water was drained 20 d before harvesting. For the SWD treatment, a ponding water depth of 0.01–0.02 m was maintained from 20 DAT to 99 DAT, and water was drained 20 d before harvesting. For the Non-flooding treatment, the plots were saturated (not flooded) from 20 to 57 DAT. After 57 DAT, a ponded water depth of 0.01–0.02 m was maintained until 99 DAT, and the water was drained 20 d before harvesting. The N fate and rice growth did not differ between the treatments during the early growth stages in response to the differences in water management. Rice root activity during the middle growth stage was higher for SWD, which was possibly because of the above-ground biomass and other factors during the middle growth stage of the rice. We found that the recovery efficiencies for N fertilizer, N uptake and above-ground biomass at the heading stage were higher for SWD than for the other two treatments. Although the soil status (reduction or aerobic conditions) was the same for the different water treatments up to the maximum tiller number stage, either the SWD or Non-flooding option could be used to conserve water. In addition, the fate of the N fertilizer, the N use efficiency, the rice growth and the rice yield were the same or higher with these two treatments than with the Flooding water management treatment.

Snow gliding and glide avalanches: a review

Snow gliding is a downhill motion of snow on the ground; it is able to affect afforestation (uprooting of plants) and to cause soil erosion. Once the glide motion turns into an avalanche movement, the process is called a glide avalanche. Winters with continuing snow gliding and a high activity of glide avalanches might be called ‘glide winters’. The most recent ‘glide winter’ in the European Alps was 2011/2012. Glide avalanches have the ability to cause damage to buildings and infrastructure. This review describes the progress in research, from basic snow glide measurements via the design of sophisticated models through to comprehensive investigations concerning glide avalanche formation. However, despite the great progress made in this field of research, there are still some unsolved problems, such as the influence of soil conditions on snow gliding or the prediction of glide avalanches.

Probabilistic Assessment of Earthquake Damage and Loss for the City of Tehran, Iran

Article history: Received: 16 February 2013 Accepted: 30 May 2013 Tehran is one of the densely populated metropolises located in earthquake-prone regions. Tehran, the population of which surpasses 8 million people, is the most populated area in Iran. There are historical evidences confirming that catastrophic earthquakes have destroyed the city in past years. In the present paper, our study covers all parts of Tehran because there is the potential of significant earthquake damage and loss for the entire city. In other words, the development of high-rise building construction in the northern part, the high density of population in the southern area including old masonry buildings, and the existence of important structures in central regions, prevent us from omitting any particular part of the city from damage assessment process. We have used two sets of last available formal data published in 1996 and 2006. To consider the influence of soil conditions, Tehran has been divided into 1246 sub regions; however, in our study the results have been presented using municipality regions and in cumulative manner. Since there is no acceptable statistical data involving estimation of non-structural damage, only structural damages have been assessed. The open source software SELENA is applied to perform probabilistic loss estimates. Due to the lack of studies providing required information from structural point of view in our country, and the existence of similarity between structural codes of Iran and that of United States, HAZUS-MH (Hazard Us – Multi Hazard Loss) structures coefficients are used. According to the results, from 1996 to 2006, the mean damage ratio and number of casualties have been reduced, while the economic loss has been increased.

Application of silver nano-particles for protection of seeds in different soils

To investigate the possibility of using silver nano-particles for protection of a living organism, wheat seeds were nano-coated and planted. Effect of nano-treatment on seed germination and protection against fungi was compared with that of a conventional preplanting fungicide (Carboxitiram). Influence of soil conditions on the effectiveness of nano-seed treatment was also investigated. Soil conditions included different levels of nutrients, pH and moisture content. Results showed that soil conditions do not affect seed protection provided by silver nano-particles against fungi, and this effect is completely independent of soil conditions. Data analysis indicated that silver nano-particles do not reduce seed germinability. Moreover, seed protection afforded by silver nano-particles and Carboxitiram was not significantly different. Thus, nano-coating may be considered as potential preplanting fungicide. Key words: Silver nano-particles, seed treatment, preplanting fungicide.

Pinyon pine (Pinus edulis) mortality and response to water addition across a three million year substrate age gradient in northern Arizona, USA

Pinyon pine (Pinus edulis Engelm.) is an important tree species in the western United States that has experienced large-scale mortality during recent severe drought. The influence of soil conditions on pinyon pine response to water availability is poorly understood. We investigated patterns of tree mortality and response of tree water relations and growth to experimental water addition at four sites across a three million year soil-substrate age gradient. We measured recent pinyon mortality at four sites, and tree predawn water potential, leaf carbon isotope signature, and branch, leaf, and stem radial growth on 12 watered and unwatered trees at each site. Watered trees recieved fifty percent more than growing season precipitation for 6 years. Substrate age generally had a greater effect on tree water stress and growth than water additions. Pinyon mortality was higher on intermediate-aged substrates (50–55%) than on young (15%) and old (17%) substrates, and mortality was positively correlated with pinyon abundance prior to drought. These results suggest high soil resource availability and consequent high stand densities at intermediate-age substrates predisposes trees to drought-induced mortality in semi-arid regions. The response of tree water relations to water addition was consistent with the inverse texture hypothesis; watering reduced tree water stress most in young, coarsely textured soil, likely because water rapidly penetrated deep in the soil profile where it was protected from evapotranspiration.

The influence of soil conditions on regeneration establishment for degraded secondary forest restoration, Southern China

To assess the impact of soil conditions on regeneration establishment we chose three diversity indexes as quantitative indicators of the understory of degraded secondary tropical forest, and selected two different function groups of species for subsequent restoration management. By applying redundancy analysis (RDA) the factors affecting understory diversity and species richness and number of different function groups were investigated. RDA showed that soil conditions had a positive effect (all contribution rates exceeded 55%) in explaining regeneration diversity, grouped species richness and number. Soil available P were the main factors affecting understory diversity and species richness, while pH value and available K were the main factors affecting species number and target species. The response of regeneration to pH value, available P and available K were different. This analysis could be used to determine suitable soil conditions for different restoration purposes. The results should be useful for effective and scientific management of regeneration restoration in the future.

Effects of Lightning Electromagnetic Pulse on a Nearby Overhead Horizontal Conductor

A nearby lightning strike can induce significant currents in long horizontal and tall down conductors. Although the magnitude of the current in this case is much smaller than that encountered during a direct strike, the probability of occurrence and the frequency content is higher. In view of this, appropriate knowledge of the characteristics of such induced currents is relevant for the interpretation of recorded currents. Considering these, the present paper discusses a modeling procedure that permits simulation of lightning-induced voltages or currents on overhead lines due to a nearby lightning strikes. In this paper, homogeneous non-perfect ground is also examined to investigate the influence of soil conditions on induced effects.

Near‐surface ground ice in sediments of the Mackenzie Delta, Northwest Territories, Canada

AbstractThe ice content of near‐surface permafrost was determined at more than 70 sites in the Mackenzie Delta, Northwest Territories. Willow and alder communities growing on aggrading surfaces with well‐drained sandy silts and ‘warm’ ground temperatures were underlain by permafrost with low ice content. Spruce forests above the level of annual flooding, lakeside alder communities in the central and southern delta, and sedge wetlands in the northern delta with moist silty loam soils, low sedimentation rates and ‘cold’ ground temperatures were underlain by medium to high ice‐content permafrost. Beneath spruce forests, a layer of near‐surface ice accumulation 1 to 2 m thick was underlain by alluvium bonded by pore ice. These profiles indicate that contemporary conditions favour near‐surface ice accumulation. The preservation of ice‐poor permafrost at depth demonstrates the limited vertical accumulation of near‐surface segregated ice. In contrast, at lakeshore alder or sedge wetlands, segregated ice extended at least 2 m below the base of the active layer, indicating that permafrost aggraded in a saturated environment. Development of ground ice in the Mackenzie Delta may elevate alluvial surfaces, modify the flooding regime, and thereby influence soil conditions and ecological succession. Copyright © 2005 John Wiley & Sons, Ltd.

モンゴル草原の土壌特性とＡＳＴＥＲデータの比較

The influence of soil condition in remote sensing data have not been clearly explained. Therefore, it is important to study the relationship between ground survey data and remote sensing data. Ground survey on soil condition such as topography, soil moisture, soil color and soil particle size were carried out in Mandal-GOBI, Mongolia on every August 1998 to 2002. The test area was covered by thin grass, the coverage ranges from 12% to 28%.Topographic survey was used kinematic GPS. Soil moisture was measured in 3cm depth by four-pin prove sensor. The measurement on ground surface was very difficult. Measured soil moisture ratio indicated 0.05 to 0.20 and topography was no related to the soil moisture. Soil color was measured by HSI value in digital camera images. The result showed soil color was almost same condition. Therefore, soil moisture and soil color was disregard in this study. Soil particle size was also measured by the digital camera images. Visual interpretation of the images was carried out to classify five categories of soil particle size.In this study, TERRA ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) image was compared with soil particle size. Firstly, ASTER image was geometrically rectified with topographic data by image matching. And topographic influence of the ASTER image was removed by logarithmic residuals method. The digital number in band 7 and band 8 had tendency to drop with large soil particle size. The digital number in Band 9 had tendency to rise with large soil particle size. Those tendencies were noticeable results in vegetated area. Therefore, vegetation condition should be discussed to understand the results.

Influence of soil conditions, spore densities and nematode age of Pasteuria penetrans attachment to Meloidogyne incognita

Several soil variables as soil texture, moisture and temperature, Pasteuria penetrans spore densities and nematode age were tested in the laboratory for their effects on spore attachment to Meloidogyne incognita juveniles. Percentage of juveniles with endospores attached and number of spores per juvenile increased with concentration of spores applied to soil. In a clay-loam soil, hundred-percent attachments were reached at densities of 5 × 105 spores per g of soil and above. Attachment was greater in loamy-sand than in sandy-loam and clay-loam soils, but lower when soil moisture was under 10% than when it was over 25%. Numbers of juveniles with spores attached were greater when soil temperatures were 25 deg C and 35 deg C than at 15 deg C and lower in 7-30 days old juveniles than in 0-6 days old juveniles. All factors that favored nematode mobility in soil increased Pasteuria spore attachment to M. incognita juveniles.

Throughfall and output fluxes of Mg in European forest ecosystems: a regional assessment

The biogeochemistry of Mg is of special importance in terrestrial ecology since Mg deficiency is a widespread phenomenon in European forests. Here, we investigate regional patterns of annual Mg fluxes with throughfall in relation to Mg outputs with seepage and runoff using published data from 71 forest ecosystems. Throughfall fluxes of Mg in this dataset are between 0.24 and 22.4 kg ha −1 yr −1 and are related to two major factors: the distance to the sea and the amount of dust in deposition. The gradient of Mg input from the sea may extend to 200 km inland. Output fluxes of Mg are on an average higher than throughfall input fluxes, with an average net loss of Mg from most ecosystems of 0.5–1.5 kg ha −1 yr −1 despite widespread Mg deficiency in European forest ecosystems. The amount of Mg leached in runoff or seepage water is largely dependent on the amount of Mg in throughfall. The influence of soil conditions and bedrock type on Mg output are surprisingly minor in this database indicating that the Mg cycle in many European forest ecosystems is to a great extent influenced by atmospheric inputs of Mg.

Influence of earthquake source parameters and damping on elastic response spectra for Iranian earthquakes

In this paper the influence of effective duration of strong motion, soil condition, magnitude and shape of accelerogram time history on the elastic response spectra has been investigated. A total of 106 of Iran's horizontal acceleration components of strong motion records are selected. These accelerograms are categorized based on their earthquake parameters and soil condition of recording station and the influence of different soil conditions are plotted in graphs. The influence of damping ratio on the response spectra is also investigated. Analytical results show that the influence of soil condition is significant for the shape of response spectra. The influence of effective duration of strong motion has been studied by definition based on the energy of the accelerogram. It can be seen that an increase in effective duration causes a reduction in the slope of response spectra in the long period part and increases the spectral values. The effect of damping on response spectra is represented by a special coefficient which depends on the period and damping of the structure and soil condition.

Inelastic Displacement Ratios for Structures on Firm Sites

The results of a comprehensive statistical study of inelastic displacement ratios that permit the estimation of maximum lateral inelastic displacement demands on a structure from maximum lateral elastic displacement demands are presented. These ratios were computed for single-degree-of-freedom systems undergoing different levels of inelastic deformation when subjected to a relatively large number of recorded earthquake ground motions. The study is based on 264 acceleration time histories recorded on firm sites during various earthquakes in California. Three types of soil conditions with shear-wave velocities higher than 180 m/s are considered. The influences of period of vibration, level of ductility demand, site conditions, earthquake magnitude, and epicentral distance are carefully evaluated and discussed. Inelastic displacement ratios associated with mean values are presented. Special emphasis is given to the dispersion of the results. It is concluded that for sites with average shear-wave velocities higher than 180 m/s the influence of soil conditions is relatively small and can be neglected for design purposes. Finally, results from nonlinear regression analyses are presented that provide a simplified expression to be used in the design to approximate mean inelastic displacements ratios for structures on firm sites.

The weed seed bank of soils in a landscape segment in southern Bavaria – II. Relation to environmental variables and to the surface vegetation

In the first part of their investigations of the weed seed bank in a 110 ha landscape segment in southern Bavaria, Albrecht & Forster (1996) showed that there was a tremendous spatial variability in seed density as well as in species composition. The intention of the present paper was to elucidate the reasons for this variability. For this purpose, the influence of soil conditions, land use practices, and soil fauna, all of which are environmental factors potentially affecting the weed seed bank, were investigated.

Influence of soil conditions on the seismic behaviour of two cable-stayed bridges : M. Elassaly, A. Ghali & M. M. Elbadry, Canadian Journal of Civil Engineering, 22(5), 1995, pp 1021–1040

Influence of soil conditions on the seismic behaviour of two cable-stayed bridges : M. Elassaly, A. Ghali & M. M. Elbadry, Canadian Journal of Civil Engineering, 22(5), 1995, pp 1021–1040

Soil Management Effects on Planting and Emergence of No-till Corn

Information is lacking on the influence of soil conditions on planting and emergence of row crops. We studied no-till planting and emergence of corn (Zea mays L.) as influenced by nine previous management practices, ranging from 6-yr bromegrass (Bromus inermis Leyss.), B6, to 6-yr conventional-till corn, C6, on a silt loam. Soil structure (air entry value, bulk density, dispersible clay, mass fractal dimension, tension draining the smallest pores, wet-aggregate stability) and water content measurements were made prior to planting. An instrumented 97 kW Case-IH Magnum tractor and a modified John Deere model 7000 planter were used for corn planting. Tractor performance and planter draft were measured with transducers and a data logger. Fuel consumption (r = 0.92), ground speed (r = 0.79), and wheel slip (r = 0.75) were linearly related to draft. Corn seedling emergence was measured 14, 18, and 22 days after planting (DAP). The effect of management was significant for two-thirds of the structure measurements, all of the equipment variables, and corn emergence 14 DAP. Planter draft ranged from 12 kN in C6 to 15 kN in B6. Wet-aggregate stability was the only structure measurement correlated with draft (r = 0.33), fuel consumption (r = 0.34), speed (r = 0.30) or slippage (r = 0.29). These relations were explained by the fact that wet-aggregate stability and draft both increase with increasing root length density. Corn emergence was more rapid in B6 than in C6, but did not correlate with any of the structure measurements. Further research is needed to determine if this result was due to improved soil structure or shallower seed placement following forages.

Influence of soil conditions on the seismic behaviour of two cable-stayed bridges

The results of a case study of the internal forces caused by earthquake in two examples of cable-stayed bridges are presented. A comparison is made between the behaviour of a model in which the structure is idealized without the foundation system and a model in which both the structure and the supporting foundation are idealized. The effects of varying the soil conditions on the seismic response are assessed. Also, the effects of out-of-phase support movements, caused by the lapse of time required for the seismic waves to travel from one support to the other, are considered. It is concluded that the effects of these parameters are significant and should not be ignored in the seismic analysis of cable-stayed bridges. Key words: bridges, cable-stayed, dynamic, earthquake, internal forces, seismic, soil–structure interaction.

A Simplified Procedure for Constructing Probabilistic Response Spectra

This paper provides a simplified procedure for computing the probabilistic maximum response of a linear single-degree-of-freedom system subjected to earthquake ground motion. The formulation uses the root-mean-square ( rms) response of the system and a probabilistic peak factor which is modified to account for the wide-band characteristics. The modification uses a set of damping-dependent coefficients obtained from correlating the peak factor with the ratio of the maximum response to the rms response from accelerograms recorded on alluvium and rock. The procedure incorporates the influence of soil condition and the strong motion duration as parameters in computing response spectra.

Supplemental nitrogen fertilizer to soybeans. IV. Influences of soil conditions on the yield response to supplemental nitrogen.

土壌条件が大豆の窒素追肥による増収効果に及ぼす影響について検討した。とくに, 窒素追肥が作物体の窒素同化に及ぼす効果を解析するため, 根粒非着生大豆系統を対照に用い, 供試栽培品種の窒素同定量, 追肥窒素の吸収量や追肥窒素による窒素固定の減少量を推定した。堆肥投与によって土壌の肥沃度を高めた時, 窒素追肥による増収量や増収率は低下した。逆に, 土壌からの窒素供給量が減少するにしたがい, 窒素追肥による増収効果は逓増した。土壌の種類が異なる場合には, 無追肥条件下での作物体の土壌窒素吸収量, 窒素固定量や全窒素同化量の大小と, 追肥の増収効果には直接的な関係は認められなかった。しかし, 開花期から最大繁茂期までの同化窒素量を高める効果が大きい土壌条件の下では, 追肥による増収効果も大きかった。追肥効果が高かった原因は, 灰色低地土のシルト質埴壌土では, 無追肥時の窒素固定機能が低く, 追肥による窒素固定の低下が少なかったためであった。主た, 灰色低地土の壌土の中には, 追肥窒素が迅速に吸収され, 追肥窒素の利用率が極めて高かったものもあった。一方, 黒ボク土の壌土は, 窒素追肥による窒素固定の減少が著しく, 同等の土性の灰色低地土の壌土に比べでも追肥効果が上がらなかった。その著しい窒素固定阻害は, 黒ボク土の可給態燐酸の濃度が低いためであると推察された。